In this project we are studying growth and the neural, biochemical, and behavioral development of nursery-reared monkeys that are at low and high risk for developmental abnormalities. High-risk "infant save" subjects have low birth weight, were born prematurely, are sick, maternally rejected and injured, or genetically abnormal animals born to members of the WaRPRC breeding colony. Low-risk subjects are healthy infants whose mothers cannot care for them because of illness, death, or assignment to experimental projects. We study these animals to (1) document the development of high-risk monkeys, (2) provide normative information for developmental experiments requiring large sample control data, and (3) develop and expand primate models of human high-risk conditions and potential models of human genetic disorders affecting developmental processes. Measures taken on these moneys range from data on body weight and skeletal and brain growth, through assessments of imm une and ho rmone status, to studies of reflexive, perceptual, learned, and social behavior spanning the period of birth through infancy. This work also provides research training for 25-30 undergraduate and 5-10 graduate students each year, and provides the material for several PhD and nursing degree candidates in most years. During the past year we continued data collection on high- and low-risk infants, we began development of a procedure for studying the stress hormone, cortisol, using saliva rather than requiring capture for blood draws, and we followed development of three monkeys born with congenital brain abnormalities. We are assessing the genetic status of the latter three animals in an attempt to locate the responsible genome mutations through perigree analyses. We believe this work may identify an important primate model of abnormal fetal brain development. Supported by NIH grants RR00166 and HD08633. Ha, J.C., Nosbisch, C., Abkowitz, J.L., Conrad, S.H., Mottet, N.K., Ruppenthal, G.C., Robinette, R., Sackett, G.P., and Unadkat. J.D. Fetal, infant, and maternal toxicity of zidovudine (azidothymidine) administered throughout pregnancy in Macaca nemestrina. J. AIDS Hum Retrovirol 18:27-38, 1998. Heath-Lange, S., Ha, J.C., and Sackett, G.P. Behavioral measurement of temperament in male nursery-raised infant macaques and baboons. Am. J. Primatol. 47:43-50, 1999. Sackett, G.P., Novak, M.F.S.X., and Kroeker, R. Early experience effects on adaptive behavior theory revisited. Ment. Retard. Devel. Disabil. Rev. 5 1-11, 1999.